Influence of liquid hydrogen sloshing on new generation aircraft composite tank. Investigation of anti-sloshing baffles and solid nitrogen foreign object debris on in-tank wall pressure and loads

The utilisation of liquid hydrogen as a propulsion fuel for next-generation aircraft necessitates the development of advanced composite tanks capable of withstanding the unique challenges posed by cryogenic fluids. In this study, we investigate the influence of liquid hydrogen sloshing dynamics on the structural integrity of composite tanks, focusing on the effects of anti-sloshing baffles and solid nitrogen foreign object debris (FOD) on in-tank wall pressure and loads. Our analyses extend to a 1100-liter tank filled with 57kg of liquid hydrogen, representative of real mission conditions, including turbulence scenarios and various fuel levels. Furthermore, we investigate the structural response under maximum load conditions, simulating 9g front load and 6g lateral load cases to comprehensively assess the tank's performance across a range of operational scenarios. In this adiabatic study, we employ a comprehensive methodology encompassing a simple dynamic pressure approach, Computational Fluid Dynamics (CFD), and Moving Particle Simulation (MPS) to analyse the sloshing behaviour of liquid hydrogen within composite tanks under various conditions. The investigation specifically focuses on evaluating the effectiveness of anti-sloshing baffles in mitigating slosh-induced pressures and loads on the tank walls, thereby enhancing structural stability and reducing potential damage. Various scenarios, including configurations with 1, 2, and 3 anti-sloshing baffles, are explored and compared to cases with no baffles to assess their impact on dynamic pressure distribution during sloshing. Furthermore, we examine the impact of solid nitrogen Foreign Object Debris (FOD) on in-tank wall pressure distribution and structural response. Given that leftover nitrogen remains present in the tank after purging, we simulate realistic scenarios to assess resulting pressures and loads on the tank walls, aiming to identify potential vulnerabilities and develop strategies for FOD prevention and mitigation. The analysis reveals that solid nitrogen FOD has a minor effect on the structural integrity of the inner tank. Additionally, our findings indicate that there is no added benefit of including rectangular anti-sloshing baffles in vertical orientation, orthogonal to the acceleration-direction for this liquid hydrogen mass. This study aims to provide valuable insights for the design and optimization of composite tanks for liquid hydrogen storage in aircraft applications.